<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <!-- 引入Bootstrap的css样式 -->
    <link rel="stylesheet" href="css/bootstrap.min.css" />
    <style>
        .container {
            outline: 1px solid black;
            margin: 30px;
        }

        .col-md-4 {
            outline: 1px solid black;
            background: pink;
        }
    </style>
    <!-- 引入jQuery -->
    <script type="text/javascript" src="js/jquery-3.3.1.min.js"></script>
    <script type="text/javascript" src="js/bootstrap.min.js"></script>
</head>

<body>
    <!-- 栅格系统最外层的容器必须是container -->
    <div class="container">
        <div class="row">
            <div class="col-md-4">col-md-4</div>
            <div class="col-md-4">col-md-4</div>
        </div>
    </div>
    <div class="container">
        <div class="row">
            <div class="col-md-4 col-md-offset-1"> col-md-4</div>
            <div class="col-md-4 col-md-offset-1">col-md-4</div>
        </div>
    </div>
</body>

</html>